700 Bulletin American Museum of Natural History [Vol. XLVI 



Crotalus exsul Garman 



Crotalus exsul Garman, 1883, p. 114; Stejneger and Barbour, 1917, p. 109. 



Range. — Southwestern California and northeastern Lower California to Cedros 

 Island. 



Lower Californian Records. — Cedros Island, Garman, 1883, p. 114; En- 

 senada, Van Denburgh, 1896, p. 1007; San Salado Canon, San Matias, Santa Cata- 

 line, Agua Escondito, Matcmi, San Quentin, Meek, 1905, p. 17; "Turtle Bay," 

 Van Denburgh and Slevin, 1921a, p. 71. 



The Albatross collection contains a single very large specimen (U. 

 S. N. M. No. 64588) of this species, without definite locality, but almost 

 certainly from Cedros Island. 



Three specimens in the collection of the Biological Survey are from 

 San Quintin (U. S. N. M. Nos. 37571-2) and San Tomas (37574). 



The characters employed by Cope in his key to the species of 

 Crotalus (1900, p. 1152) to distinguish Crotalus ruber ( = exsul) are some- 

 what misleading, especially as he separates ruber widely from atrox which 

 I believe to be its nearest relative. There is a tendency to widening of 

 the rostral, and to obscurity of the canthus rostralis in exsul, but neither 

 character is constant, and the reddish coloration must be relied on in 

 most cases as a key character. 



Crotalus enyo (Cope) 



Caudisona enyo Cope, 1861, p. 293. 



Crotalus enyo Stejneger and Barbour, 1917, p. 109. 



Range.— Southern Lower California. 



Lower Californian Records. — Cape St. Lucas, La Paz, Yarrow, 1882, p. 74; 

 San Jose del Cabo, Van Denburgh. 1895, p. 157; Mulege, Mocquard, 1899, p. 333; 

 Miraflores, San Antonio, Todos Santos, San Bartolo, San Pedro, Sierra Laguna, Van 

 Denburgh and Slevin, 1921a, p. 71. 



A specimen collected by the Biological Survey, U. S. N. M. No. 

 37570, is from Santa Anita. 



Crotalus cerastes Hallowell 

 Crotalus cerastes Hallowell, 1854, p. 95; Stejneger and Barbour, 1917, p. 108. 



Range. — Southwestern Utah to southeastern California and northeastern Lower 

 California. 



Lower Californian Records. — San Felipe, Meek, 1905, p. 18. 



Four specimens in the collection of the Biological Survey are from 

 San Felipe Bay (U. S. N. M. Nos. 37562-3), Cocopah Mountains, east 

 base (37564), and San Francisquito (37565). 



Crotalus mitchellii (Cope) 



Caudisona mitchellii Cope, 1861, p. 293. 



Crotalus mitchellii Stejneger and Barbour, 1917, p. 110. 



Range. — Southwestern Arizona to southern Lower California. 



